1. Field of the Invention
This invention relates to the construction of battery powered illuminated hand tools and specifically to the mechanism for applying power to the light source thereof.
2. Prior Art
Illuminated tools, such as a screwdriver, have long been available. Various such tools are shown in the U.S. patents, for example: U.S. Pat. Nos. 1,635,933 to Genoves; 2,242,536 to Montgomery; 2,408,601 to Blauvelt; 2,736,792 to Freeland; 3,185,832 to Nagamori; 2,670,427 to Barlet et al. These patents illustrate various structures designed to provide light at the end of the tool. They also illustrate various mechanisms for applying and removing power from the light bulb.
Typically a light bulb is provided with a threaded base portion, the threads of which define one terminal of the bulb. The base also has a protrusion from its end defining the other terminal of the bulb. A power source, such as a battery, has one terminal held against a terminal of the bulb by a spring. The other (distant) terminal of the battery is connected to the threaded terminal of the bulb by a discontinuous electrical path which is generally made continuous by moving a slide switch. Such a mechanism is shown in the U.S. patents to Blauvelt, Freeland and Nagamori.
Other methods for closing the discontinuous electrical path from the bulb to the far terminal of the power source include the use of a metal screw mounted to the base of the handle of the tool. When the screw is rotated, it advances toward and contacts the terminal of the power source completing the electrical circuit. Such are the devices of Genoves (U.S. Pat. No. 1,635,933) and Barlet et al. (U.S. Pat. No. 2,670,427).
Another mechanism is shown in Montgomery (U.S. Pat. No. 2,242,536) where contact with the far terminal of the battery is made by a spring 24 connected to a strip 23 which may be rotated to make or break connection with a strip 25 connected to the light bulb.